1. Field of the Invention
The present invention relates to a manufacturing method for products in a manufacturing line having a step of installing a module to a main body, and more particularly to a manufacturing method for an exposure apparatus which is used when a mask pattern is transferred onto a substrate in a lithography step for manufacturing such devices as a semiconductor device, image pickup device (e.g. CCD), liquid crystal display device, plasma display device and a thin film magnetic head. The present invention also relates to an exposure apparatus which is manufactured using this manufacturing method.
2. Description of the Related Art
In a photolithography step for manufacturing semiconductor devices, full field exposure type (stepper type) or scanning exposure type (e.g. step and scan type) exposure apparatuses are used to transfer a pattern of a reticle (e.g. photo mask) as a mask onto a wafer (or glass plate) as a substrate. In these exposure apparatuses, exposure wavelengths are becoming shorter, from KrF excimer laser 248 nm to such a vacuum ultra-violet region as ArF excimer laser 193 nm and F2 laser 157 nm in order to support semiconductor devices which are becoming even smaller at increasing degrees of integration. Also the size of projection optical systems are becoming quite large since a 0.65 or higher numerical aperture is becoming necessary in a wide visual field. In a scanning exposure type exposure apparatus, exposure onto a required size of shot area, while controlling the scale of the projection optical system to a practical range, is becoming possible by setting the scanning direction to a direction which is perpendicular to the direction where the visual field of the projection optical system is widest.
Conventional exposure apparatuses are generally manufactured by installing a box type column on a base panel, installing a wafer stage system at the center of the column, then stacking up each mechanism section of the projection optical system, reticle stage system and illumination optical system on the column. When installing each mechanism section, measurement is performed to check the mutual positional relationship, if necessary, and the positional relationship is adjusted based on this measurement result. In this case, the wafer stage system and reticle stage system are roughly pre-assembled on a dedicated adjustment jig, which is disposed at a location different from the location where the base panel is installed.
As mentioned above, a conventional exposure apparatus is manufactured by a stacking system where each mechanism section is sequentially stacked up, wherein the stage system is pre-assembled using a dedicated adjustment jig. For current exposure apparatuses, however, the sizes of the exposure light source and projection optical system are increasing, and a high throughput is demanded, so in order to improve the operation efficiency of the projection optical system, a double stage type, where two movable stages are used for the wafer stage system, has been proposed. In this type, while exposing a wafer on one movable stage, a wafer on the other movable stage is replaced or aligned so as to improve throughput. For the reticle stage side, as well, a double holder type, where two reticles are held on one movable stage, is being used so that two reticles can be used alternately. The double stage type is disclosed, for example, in PCT International Publication No. WO98/24115 (corresponding to U.S. patent application Ser. No. 09/714,943) or WO98/40791 (corresponding to U.S. Pat. No. 6,262,796), and the double holder is disclosed, for example, in Japanese Patent Application Laid-Open No. 10-209039 (corresponding to U.S. Pat. No. 6,327,022).
However, if a stage system is assembled using a dedicated adjustment jig in a conventional way, with a large size wafer stage system and reticle stage system, the size of the dedicated adjustment jig increases, and the entire installation area of the manufacturing equipment for an exposure apparatus increases too much. Also, it is difficult to prepare such a large size dedicated adjustment jig for each model of exposure apparatus, and even if such a dedicated adjustment jig is prepared, the manufacturing efficiency of exposure apparatuses drops because the operation of the large size dedicated jig. Direct assembly of these stage systems on the column without using an adjustment jig, on the other hand, interfere with the adjustment and installation operation of other mechanical sections, such as the illumination system and projection system. These stage systems also require a performance evaluation before being installed to an exposure apparatus. For this, these stage systems must be pre-assembled as modules before installing to an exposure apparatus.
Also, it is demanded that exposure apparatuses in use today must have a structure which minimizes the influence of vibration to improve the exposure accuracy (e.g. transfer fidelity, alignment accuracy). Especially for scanning exposure type exposure apparatuses, vibration generated by acceleration and deceleration must be decreased because a reticle and wafer are scanned during exposure, with the magnification of the projection optical system as the velocity ratio. However, in the case of an exposure apparatus having a structure where each mechanism section is sequentially stacked up on a base panel, vibration generated in the stage system tends to transfer to each mechanism section, and this vibration also tends to transfer to the projection optical system.
So a structure which can decrease the influence of vibration more than previously has been developed for exposure apparatuses, but even with such a structure, it is generally desirable to manufacture each exposure apparatus in a short time, making the manufacturing efficiency as high as possible. With the foregoing in view, it is a first object of the present invention to provide a manufacturing method for exposure apparatuses which can manufacture exposure apparatuses efficiently without using dedicated large adjustment jigs.
It is a second object of the present invention to provide a manufacturing method for exposure apparatuses which can efficiently manufacture exposure apparatuses having a structure to efficiently decrease the influence of vibration. It is still another object of the present invention to provide an exposure apparatus with a structure suitable for manufacturing using such a manufacturing method, and a manufacturing method for high precision devices using this exposure apparatus. It is still another object of the present invention to improve the operation efficiency and productivity in a manufacturing line having a step of installing a module to a product main body.